haswell



UNITED STATES PATENT OFFICE.

ALEXANDER ELLIOT HASWELL AND ARTHUR GEO. HASWELL, OF VIENNA, AUSTRIA-HUNGARY.

COATING METALS AND ALLOYS WITH OXIDES.

SPECIFICATION forming part of Letters Patent No. 476,639, dated June 7, 1892.

Application filed February 10, 1892. Serial No. 421,039. (Specimens) To aZZ whom it may concern:

Be it known that we, ALEXANDER ELLIOT HAsWELL and ARTHUR GEORGE HAsWELL, both subjects of the Queen of England, and residents of the city of Vienna, Empire of Austria-Hungary, have invented certain new and useful Improvements in Coating Metals and Alloys With Oxides, of which the following is a specification.

In order to be able to give copper and alloys of this metal with tin, zinc, and nickel a coating of binoxide of lead and binoxide of manganese as obtained by our process for coatingmetals with oxides, PatentNo. 453,355, dated June 2, 1891, We have made the following alteration in the composition of our bath, employing nitrate of soda or nitrate of potash instead of nitrate of ammonia as a conducting-salt.

For preparing the bath eighty grams of nitrate of lead are dissolved in five hundred grams of water, and this solution is poured into six hundred and thirty-five grams of caustic-soda solution, the latter solution having a specific gravity of 1.27, equal to 3l Ban me, and therefore containing one h undred and fifty-eight grams caustic soda. If a solution of caustic potash is used instead, it has to be of equivalentstrength. After mixing the whole, ten grams of finely-powdered carbonate of manganese are added and the bath is well stirred,either by hand or in any convenient way, during the electrolysis.

The addition of carbonate of manganese is quite essential,for Without it the coatings on copper and its alloys show not alone a difference in color, but also in aggregate, being less hard and dense, and chemical analysis of the deposit prepared in a bath containing carbonate of manganese shows the presence of manganese in the form of binoxide, which is deposited, along with the binoxide of lead, onto the article under treatment.

Similar to our previous invention for coatin g iron, steel, and other metals with binoxide of lead and man gauese, the article to be coated is first carefully cleaned by means of any well-known method employed in the usual processes of electro-deposition, in order to remove all oXides and fatty material. The article to be coated is immersed in the said bath after being attached to the positive pole of a galvanic battery or dynamo-machine, and an electric current is passed through the bath until the deposit on the article has obtained the required thickness. In practice good results have been attained with an electric current of one-half to one ampere per square decimeter surface of the article to be coated and a tension of from two to two and one-half volts. The temperature of the bath may vary from or to 75 Fahrenheit. A deposit of suitable thickness is formed after about ten minutes exposure in the bath.

\Ve claim as our invention- The hereinbefore-described process of electro-depositing binoxide of lead and binoxide of manganese on copper and its alloys, which consists in immersing the article to be coated in a bath containing nitrate of lead and carbonate of manganese suspended in a solution of caustic soda or caustic potash and in depositing the said oxides from the said bath by passing an electric current from the article through such bath.

In testimony whereof We have affixed our signatures in presence of two witnesses.

ALEX. ELLIOT HASWELL. ARTHUR GEO. HASiVELL. \Vitnesses:

P. 0. PAGET, '1. G. HARDY. 

